Doubt: IF statement on a cell

Doubt: IF statement on a cell

The formula in K2 is saying: IF in J2 is saying “L” , then calculate the total in K2 = I2+40
But
IF in J2 is saying “M” , then calculate the total in K2 = I2+15
But
IF in J2 is saying “R” , then calculate the total in K2 = I2+30

Also, formula in K2 MUST BE equal or bigger then cell E2. If not, cell K2 must be = 3% * E2

Can anyone help me with this formula? Tks!